#include<stdio.h>
#include<unistd.h>
#include<stdlib.h>
#include<sys/types.h>
#include<wait.h>
int main()
{
  printf("程序开始运行：\n");
  sleep(1);
  if(fork()==0)
  {
    execl("/usr/bin/ls","ls","-a","-l",NULL);
    exit(1);
  }
  waitpid(-1,NULL,0);
  printf("程序运行完成！！\n");
  return 0;
}
